Answer:
If you were to go north from the Sahel, you'd find the Sahara. If you were to go south from the Sahel, you'd find tropical grasslands.
The Sahel is a transitional region in Africa that lies between the Sahara Desert to the north and the tropical grasslands to the south. As you move north from the Sahel, you would encounter the Sahara Desert, which is the largest hot desert in the world, covering over 3.6 million square miles across North Africa.
As you move south from the Sahel, you would encounter the tropical grasslands, which are characterized by tall grasses and scattered trees. These grasslands are also known as savannas and cover a large part of Africa, as well as other parts of the world such as South America and Australia.
Therefore, the correct answer is B. tropical grasslands; Sahara.